1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly to a gate voltage controlling apparatus and method wherein a gate voltage can be applied to a gate driver sequentially from a lower voltage followed by a higher voltage for the purpose of stably driving and protecting the gate driver, thereby minimizing any defects in the gate driver.
2. Discussion of the Related Art
Generally, liquid crystal displays (LCD) are being more widely used because of its desirable characteristics, such as light weight, thin profile and low power consumption, etc. Accordingly, the LCD has been used for office automation equipment and video/audio equipment, etc. The LCD controls the amount of light transmitted in response to a data signal applied to a plurality of control switches arranged on a liquid crystal display panel in a matrix to thereby display a desired picture on the screen.
In the liquid crystal display panel, a plurality of data lines and a plurality of scan lines are arranged to cross each other and liquid crystal cells between upper and lower substrates are arranged in a matrix. Further, the liquid crystal display panel is provided with pixel electrodes and common electrodes for applying an electric field to each liquid crystal cell. The crossings between the plurality of data lines and the plurality of scan lines is provided with thin film transistors (TFT's) for switching a data voltage to a pixel electrode in response to a scanning signal. In such a liquid crystal display panel, gate drive integrated circuits are electrically connected, via a tape carrier package (TCP), to data drive integrated circuits.
FIG. 1 schematically shows a typical liquid crystal display module.
Referring to FIG. 1, the liquid crystal display module includes a liquid crystal display panel 10, a data driver 12, a gate driver 13, and a source printed circuit board 11 provided with first and second power supplies 14 and 15. A gate high voltage VGH and a gate low voltage VGL generated by the first and second power supplies 14 and 15 are applied, via a line on glass (LOG), to the gate driver 13. At this time, although the gate high voltage VGH and the gate low voltage VGL have a voltage difference from each other, they are applied to the gate driver 13 irrespective of a certain sequence according to a voltage level. For this reason, if the gate high voltage VGH having a 20V higher level than the gate low voltage VGL is applied to the gate driver 13 at an earlier time than the gate low voltage VGL, there may be caused a damage of the gate driver 13.